The present invention relates generally to robotic paint applicators and, particularly to an apparatus for changing the paint color for a waterborne bell applicator.
Robotic paint applicators for assembly lines are well known in the art. In order to be most efficient on a vehicle assembly line, for example, the robotic paint applicators must be able to paint with a variety of different colors changing as the objects to be painted are presented. A problem found in the prior art waterborne paint bell applicators when changing paint colors was a high cycle time. Cycle time is the amount of time needed to change from a current paint color to a new paint color, measured from the time the applicator stops painting with the paint color currently being applied to the time it starts painting with a different paint color. During this cycle time, the high voltage power supply must be disconnected, the internal passages and the external shroud of the bell applicator must be cleaned and the applicator must be connected with a source of the new paint color. Prior art applicators accomplished the color change by either switching connections between separate remote storage tanks for the current color paint and the new color paint, swapping an on board canister of the current color paint for a substitute canister filled with the new color paint, or cleaning the current color paint from the on board canister and filling it with the new color paint.
The U.S. Pat. No. 4,785,760 shows a sprayer installation having a paint sprayer carried by a robot with an arm for spraying objects carried by a conveyor. Circuits for distributing products to be sprayed each have first connection means at fixed locations within the range of the robot. A storage tank connected to the sprayer is carried by the robot and communicates with a first complementary connection means. The first complementary connection means is co-operable with the first connection means of any of the distribution circuits during which time the high voltage is turned off. The storage tank can be retained on the arm or can be exchanged for a filled tank at the first connection means.
The U.S. Pat. No. 5,772,125 shows a machine for spraying a coating material which machine includes a sprayer, an on-board supply tank having first connection means, a coating material changing assembly having second connection means, and a mobile subassembly carrying the sprayer, the supply tank and the changing assembly. At least one of the connection means is movable between a coupling position and an isolated position relative to the other connection means.
The art continues to seek improvements in reducing both the cycle time and in the amount of wasted paint during a color change operation. Reducing the cycle time increases both painting capacity and production capacity because more objects can be painted in a given amount of time. Reducing the amount of paint used by the robotic paint applicator represents an obvious cost savings.